The growth of emergent communication systems in both the industrial and commercial sectors has created a strong demand for extremely wideband radio systems capable of handling multi-Giga-bits-per-second (Gbps) data rates. More precisely, the desire for general-use ‘5G and beyond’ radios require architectures with continuous operation across the whole millimeter-wave (mm-wave) spectrum up to the sub-terahertz (sub-THz) bands. However, a major barrier against achieving that goal is the associated signal loss that results from the large path loss and atmospheric absorption at those frequencies. High gain multi-antenna radios are a potential solution, but they require massive hardware, making them unsuitable for 5G devices. To reduce hardware requirements, research has been focused on implementing fully digital transceivers to replace most of the analog hardware with software operations. This hardware-to-software convergence is still limited to low frequencies and remains relatively expensive. This CAREER presents novel techniques to implement a universal radio architecture for operation across legacy, 5G, and future 6G bands using a single multifunctional and adaptable platform. This research will lead to improvement in terrestrial, airborne, satellite, and vehicle-to-vehicle communications. Also, mm-wave and sub-THz systems will enable assistive technology via miniature medical, wearable, and implantable devices. Therefore, this research will have significant societal benefits impacting daily life for all. The research proposed in this project will be integrated with the principal investigator’s educational plans to develop new courses for both undergraduate and graduate students with focus on 5G and mm-wave transceivers. Efforts will also be taken to broaden the participation of underrepresented groups in STEM via curriculum development, undergraduate research programs, and outreach efforts. A new STEM outreach program on hands-on activities on radio communications will be established that involves the children of formerly homeless population, predominantly Hispanics and African Americans, individuals with disabilities, substance use, and mental health disorders. The goal of this project is to study, design, and develop wideband multifunctional adaptable transceivers for operation across the 5G, mm-wave, and sub-THz spectrum. To date, transceivers that can handle extremely wide operational bandwidths are not available. Indeed, current radios suffer from several bottlenecks: 1) antennas suffer from size-bandwidth-gain tradeoffs and are very lossy at high frequencies (i.e. mm-wave and sub-THz), 2) wideband radio frequency (RF) components are costly, lossy, and nonlinear, 3) high speed digitizers are power hungry and cost prohibitive, and 4) baseband digital electronics and software defined radios (SDR) are limited to narrowband and low frequency operations. This CAREER addresses these issues and brings forward innovative techniques to implement a universal radio with ‘on demand’ operation from a few hundred MHz to sub-THz frequencies using a single multifunctional and upgradable platform that combines 1) extremely wideband and reconfigurable aperture-in-aperture radiator, 2) high frequency modular and tunable RF front-ends that are inexpensive and power efficient operating from UHF (300MHz) up to sub-THz (300GHz) bands, and 4) physical layer interference suppression techniques. Importantly, the proposed radio is upgradable with evolving SDR technologies. That is, as SDR frequency coverage expands into emergent bands and becomes more affordable for commercial use, the RF hardware will be replaced with software operations. This hardware-to-software convergence will contribute in further reduction of the modular hardware whereby more RF modules will be integrated in the SDR. The long-term vision of this project is to implement an affordable and efficient fully digital system, with minimum hardware, operating from the low microwave frequencies up to the mm-wave bands. Overall, the proposed architecture will enable interference resiliency with increased spectral efficiency, spatial filtering, and concurrent beams across extremely large bandwidths.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
